<p>This commentary reconsiders the debate on the reliability of the serological tests used to determine the ABO blood group found in ancient human biological tissues and Christian relics, particularly in response to the recent critique by Kelly Kearse. It is known that the results of investigations on the Passion relics and some Eucharistic miracles converge on the rarest AB group. The issue of the suboptimal specificity of these tests, due to possible bacterial and fungal contamination, is also acknowledged. However, despite these limitations, the great value demonstrated by these techniques in the reconstruction of the history of the origin of mankind and human migrations should not be ignored, especially given that DNA testing was not yet available in the 1970s and 80s. This article cautions against rejecting an important wealth of knowledge obtained by authoritative researchers, who applied rigorous scientific standards to their studies. Control group tissue samples were also extensively used in the analyses of Christian relics, and despite the limitations of serological tests, the identification of the same blood group in these studies was so widespread that it cannot be underestimated. The inclusion of Eucharistic miracles in peer-reviewed literature marks a significant step in bridging faith and science, encouraging a more open and multidisciplinary inquiry into these fascinating relics.</p>